The phonological system of a specifically language-impaired population

This paper provides a characterization of the phonological system of a family of specifically language-impaired (SLI) individuals. Morphological and syntactic data from these same subjects have previously been presented in Gopnik and Crago (1991) and Guilfoyle (1991). Data were collected from eight subjects, all family members, ranging from 7 to 46 years of age. Language samples were obtained at two sessions, 17 months apart, and analysed according to a revised version of the phonological assessment procedures outlined in Ingram (1981, 1989). Results indicated that these SLI subjects acquired the phonological inventory of English following the normal developmental sequence, but at an extremely delayed rate. In contrast, these subjects never achieved adult competency in reproducing the complex syllable patterns of English, as evidenced by the fact that consonants in syllable-final position and clusters were particularly susceptible to deletion or substitution errors. It is argued that these data are consistent with a linguistically based account of this impairment, which is manifested in the phonological component by the inability to construct learned, language-specific rules.